Low cognitive competence as a vulnerability factor for behavioral despair in rats

Abstract

Elucidating the multi-faceted relationship between cognitive competence and affective states is a major pursuit in behavioral sciences. Mood disorders constitute a good research model for this question, as cognitive impairment may accompany clinical depression and persist after full remission. This suggests cognitive dysfunction as an etiological factor of depression, rather than an epiphenomenon. Complementing clinical studies, animal models utilizing well-controlled, systematic paradigms are essential to elucidate the complex relationship between cognitive competence and affective states. In current set of experiments, we investigated the extent to which cognitive competence determines the stress response in Wistar rats by utilizing two well-established spatial memory paradigms with different degrees of complexity together with the forced swim test. We revealed that rats with low cognitive competence as assessed by learning performance in the Y-Maze, but not in the radial arm maze, were significantly more vulnerable to behavioral despair. In contrast, rats with high cognitive competence were resilient to the negative effects of the forced swim test, irrespective of the spatial memory task used. These results point to a nonlinear relationship between spatial memory performance and behavioral despair, suggesting that different types of cognitive functioning may have differential effects on affective processes.